As COVID-19 continues to impact every aspect of our lives, many people are wondering what they can do to stay healthy. In addition to practicing diligent hygiene and social distancing measures, the foods you eat for breakfast, lunch and dinner can support your immune system.
The strength of your immune system and its ability to fight off infectious disease is heavily influenced by the quality and diversity of your diet. Vitamins, minerals and antioxidants found within whole, minimally processed foods are vital to supporting your body’s natural defenses. Additionally, fiber found exclusively in plant food provides nourishment for your gut microbiota, which houses over 70% of the cells that makeup your immune system. A high fiber diet has been found to promote the production of anti-inflammatory proteins which stimulate the body’s army of infection fighting cells.
Nutrient deficiencies suppress the immune system.
Deficiencies of vital nutrients suppress the immune system by weakening its ability to destroy infected cells and generate antibodies. As a whole, Americans are well fed but undernourished, due in large part to nutrient-poor, ultra-processed foods. Data from the National Health and Nutrition Examination Survey (NHANES) indicates that Americans that nearly one-third of Americans are at risk of at least one vitamin deficiency or anemia.
The more you fill your plate with nutrient-rich foods – think fruits, vegetables, whole grains, beans, nuts and seeds – the more likely you are to meet your nutrient needs and resist infection or fare well if you are infected. While it is not yet known what or how specific nutrients affect COVID-19, we do know that a minimally processed, plant-predominant diet is important for supporting your immune system.
Certain vitamins and minerals are especially important for immune function, such as Vitamins A, C, D and E, along with B vitamins, iron, zinc and selenium. While it may seem easiest to take vitamin and mineral supplements, your journey to good health and a strong immune system should begin with nutrient-dense foods. Minimally processed foods, especially plant foods, provide a balanced symphony of fiber, vitamins, minerals, antioxidants and phytochemicals that your body needs to feel well and thrive. Here are some foods to prioritize that include these vital nutrients!
- Sweet Potatoes and Carrots – Sweet potatoes, carrots and leafy green vegetables are potent sources of beta carotene, an antioxidant that converts to Vitamin A in the body. Vitamin A is an important nutrient for cell division which is vital to the body’s development of disease-fighting cells. Munch on baby carrots for an afternoon boost or savor hearty burritos for dinner filled with warming spices, cooked sweet potatoes and kale.
- Bell Peppers – One medium bell pepper will exceed your daily requirements for Vitamin C, with red bell peppers providing the most. Vitamin C is under consumed by many Americans and getting more than the recommended daily allowance (RDA) has been found to further support the immune system. Raw, stir-fried or roasted, make bell peppers a regular part of your weekly routine.
- Almonds and Avocados – Healthy fats like almonds and avocados are good sources of Vitamin E, an antioxidant that helps prevent inflammation and protects cells from oxidative damage. Grab a small handful of almonds for a simple snack or toast sliced almonds for a nutty addition to salads and oatmeal. Did you know you can freeze avocado? Slice and freeze, then add to smoothies for a lush and creamy, shake-like texture.
- Brazil Nuts – Brazil Nuts are rich in selenium, a trace mineral and antioxidant essential to your defense systems. Just one nut per day will meet your daily needs!
- Beans and Lentils – Beans (of all varieties) and lentils are rich in iron and zinc. Iron plays a structural and functional role, helping produce T lymphocytes and reactive oxygen species that kill pathogens. Zinc is essential for the development of white blood cells and the synthesis of antibodies. Canned or dried, beans and lentils make hearty and delicious editions to crunchy salads, warming soups, cozy grain bowls and veggie burgers.
- Marinara Sauce – Just 1 cup of marinara sauce is an excellent and delicious source of Vitamin B3 and B6. Vitamin B3 has potent anti-inflammatory effects and has proven to be effective in preventing lung tissue damage during ventilator-induced lung injury. Vitamin B6 participates in over 100 reactions in the body and deficiency severely dampens the acquired immune response. Try pairing homemade marinara sauce with lentil pasta and frozen broccoli for a hearty and nutritious meal.
- Fortified Foods – Vitamin D is notoriously difficult to obtain from food sources alone, so fortified foods like non-dairy milks and cereals, or supplementation may be required. Vitamin D is a key player in your body’s innate immune response, helping to fight off harmful bacteria, viruses and fungi. Deficiency of Vitamin D is associated with higher risk of upper respiratory tract infections (URI), while supplementation of Vitamin D has been found to reduce the risk of URIs. In addition to fortified food and supplementation, try boosting your body’s natural production of Vitamin D by getting outside for a 10 to 30 minute walk mid-day.
While diet alone cannot prevent or treat illnesses or infections, good nutrition and other lifestyle measures are powerful ways to support your body’s natural defenses. Health is a daily and intentional practice. Day after day, focus on filling your plate with a diverse selection of plant foods and know that you are supporting your body’s immune system!
This information was provided by Alexandra Regalado, Registered Dietitian and Nutritionist with El Camino Health’s Lifestyle Medicine Program.
- Grant WB, Lahore H,. McDonnell SL, et al. Vitamin D supplementation could prevent and treat influenza, coronavirus, and pneumonia Infections. Preprints. 2020;202003023
- Childs CE, Calder PC, Miles EA. Diet and Immune Function. Nutrients. 2019;11(8):1933. Published 2019 Aug 16. doi:10.3390/nu11081933
- Wu D, Lewis ED, Pae M, Meydani SN. Nutritional Modulation of Immune Function: Analysis of Evidence, Mechanisms, and Clinical Relevance. Frontiers in Immunology. 2019;9. doi:10.3389/fimmu.2018.03160.
- Angelo G. Immunity in Brief. Linus Pauling Institute. https://lpi.oregonstate.edu/mic/health-disease/immunity-in-brief#osu-top-hat. Published February 2017.
- Bird JK, Murphy RA, Ciappio ED, McBurney MI. Risk of Deficiency in Multiple Concurrent Micronutrients in Children and Adults in the United States. Nutrients. 2017;9(7):655. Published 2017 Jun 24. doi:10.3390/nu9070655
- Zhang L, Liu Y. Potential interventions for novel coronavirus in China: A systematic review. Journal of Medical Virology. 2020;92(5):479-490. doi:10.1002/jmv.25707.